Composition and process for metal forming



United States Patent Office 3,454,495 Patented July 8, 1969 3,454,495 COMPOSITION AND PROCESS FOR METAL FORMING Horst Schneider, Nieder-Eschbach, Germany, assignor to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Filed Aug. 8, 1966, Ser. No. 570,696 Claims priority, applicatigg Germany, Sept. 1, 1965,

49 Int. Cl. C10m 5/14, 7/20, 7/24 U.S. Cl. 25221 10 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an improved method for the cold forming of metal and more particularly it relates to a novel lubricant composition and the process using this composition in metal deformation.

In the cold forming of metals, such as in deep drawing, cold flow extrusions, the drawing of tubes and wires, and the like, it is known to use a liquid or paste like lubricant material which contains fats, mineral oils, soaps, fatty acids, or other similar lubricating components. It is also well known in the art that the effectiveness of such lubricant compositions can be increased by including in the composition a pigment material. Materials such as bentonite, colloidal clays, chalk, amorphous silicic acid, borax, as well as solid dry lubricant materials, such as graphite and molybdenum disulfide, are typical of those which have been used. Although in some instances, all of these pigment materials have been found to be effective, frequently the greatest improvements in lubricant action have been obtained when using components which have a layer structure, such as graphite and molybdenum disulfide. Although these materials do have superior lubricating properties, their use has been found to be somewhat disadvantageous in that they are very difiicult to remove from the metal surfaces after the forming operation.

It is, therefore, an object of the present invention to provide an improved lubricant composition which has the superior lubricating qualities of graphite and molybdenum disulfite containing compositions but which is not subject to the cleaning difficulties encountered with such compositions.

A further object of the present invention is to provide an improved method for the cold forming of metals, which method utilizes the improved lubricant compositi-on as set forth hereinabove.

These and other objects will become apparent to those skilled in the art from the description of the invention which follows.

Pursuant to the above objects, the present invention includes a liquid lubricant composition comprising an organic lubricant material and at least one porous, capillary active, inorganic pigment, swellable in alkaline solution, the pores of which pigment are at least partially impregnated with a thermoplastic plastic. It has been found that these compositions are at least as effective as lubricants as the lubricant compositions containing dry lubricants, such as graphite or molybdenum disulfide, while being much more easily removed from the metal surface after the forming operation. Moreover, it is found that these lubricants can be formulated in a uniform dispersion Whose uniformity will be maintained over extended periods of time.

More specifically, the composition of the present invention comprises an organic lubricant base, preferably containing from about 1 to 30% by weight of the composition, of a porous, capillary active, inorganic pigment, swellable in alkaline solution, the pores of which pigment material are at least partially impregnated with a thermoplastic plastic. The organic lubricant material which forms the base of the present lubricating composition may be any suitable organic lubricant, as is known to those in the art. Thus, for example, the organic lubricant material is preferably selected from the group consisting of oils, fats, fatty acids, fatty acid soaps, or the like. Typical of the lubricant materials which may be used are aliphatic compounds containing from about 12 to 30 carbon atoms, in a straight or branched chain, which compounds may be either saturated or unsaturated. Typically, these materials include mineral oils and fatty oils, such as cod liver oil, halibut oil, herring oil, menhaden oil, porpoise oil, salmon oil, sardine oil, shark oil, tuna oil, olein, palmitin, stearin, coconut oil, nutmeg oil, palm oil, peanut oil, whale oil, mustard oil, and the like. The lubricating component may also include the various fatty acids of these oils, such as lauric acid, myristic acid, palmitic acid, stearic acid, orachidic acid, behenic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, clupau-odonic acid, and the like, as well as the various water soluble and/or dispersible soaps of these acids, particularly the alkali metal soaps such as the sodium soaps.

Various porous, capillary-active pigments may be used in the present lubricant composition, as are known in the art. Exemplary of such pigments are silica xero gels, such as silica gel, diatomaceous earth, fullers earth, bentonite, montmorillonite, artificial and natural zeolites, aluminum hydroxides, and the like. Of these, the aluminum hydroxides have been found to be particularly suitable and, hence, for many applications are preferred.

The thermoplastic plastics, with which the pores of the inorganic pigment material are at least partially impregnated may be various thermoplastic materials such as, polyethylene, polypropylene, polyisobutylene, polyamides, polyurethanes, polyurea, polyacrylamides and the like. Desirably, the thermoplastic used is one having a relatively low melting point, thermoplastic materials having a dropping point within the range of about to degrees centigrade being preferred. In many instances, polyethylene having a dropping point within the above range has been found to be particularly suitable, so that hereinafter, primary reference will be made to this material.

In effecting the at least partial impregnation of the porous inorganic filler or pigment with the thermoplastic plastic, the plastic is preferably heated to a temperature above its dropping point and then intimately admixed with the inorganic pigment using any suitable mixing apparatus, such as a kneader or mixing rolls. If desired, the inorganic pigment material may be preheated, prior to the addition of the thermoplastic material, thus helping to maintain the thermoplastic material in the non-solid state during the mixing operation.

Following the mixing of the thermoplastic plastic and the inorganic pigment, the resulting composition may be solidified by cooling and then ground to a suitable particle size for addition to the lubricant composition. Alternatively, however, the mixture of the thermoplastic material and the pigment, while still in the plastic state, may be mixed directly with the lubricant composition. In either instance, there is obtained a lubricant composition, in

which the impregnated pigment material is finely dispersed throughout the composition.

As has been noted hereinabove the lubricant portion of the composition may be made up of one or more of various oils, fats, fatty acids, soaps, or the like. As is known in the art these lubricant compositions are desirably liquid. Preferably the liquid phase is water, so that the composition is an aqueous solution or dispersion of the lubricant material, which may, if desired, contain suitable emulsifiers or be a combination of an aqueous phase and a second emulsified liquid phase, such as an emulsified mineral oil. Alternatively, the liquid phase of the lubricant composition may be essentially a mineral, vegetable or animal fat or oil or mixtures thereof, rather than water. Although, as has been noted hereina bove, the impregnated inorganic pigment is preferably present in the lubricant compositions in amounts within the range of about 1 to 30% by weight of the composition, the amount of the impregnated pigment may be varied within broad limits so that in some instances, amounts outside of this pre ferred range may be used.

In order that those skilled in the art may better understand the present invention and the manner in which it may be practiced, the following specific examples are given. In these examples unless otherwise indicated, temperatures are in degrees centigrade and parts and percents are by weight. It is to be appreciated, however, that these examples are merely exemplary of the present invention and are not to be taken as a limitation thereof.

EXAMPLE 1 177.5 grams of polyethylene, having a dropping point within the range of 112 to 118 degrees centigrade, were placed in a heatable kneader and melted at 130 degrees centigrade. To the melt was then added 365 grams of magnesium-aluminum silicate (fullers earth). The resulting mixture was kneaded for 30 minutes. To the still plastic mixture was then added a mixture of 170 grams of olein, 14 grams of a nonionic emulsifier, 113.5 grams of water and 170 grams of the potassium salt of fish oil fatty acid. The resulting composition was mixed until there was obtained a white, paste-like lubricant concentrate. This concentrate was formed into working lubricant compositions by diluting the concentrate with water in various ratios of concentrate to water within the range of 1:1 to 1:10. The lubricant dispersions obtained were then used in the deep drawing of thick-walled sheets of cold rolled steel having a thickness of two millimeters. After drawing, the sheets showed no evidence of grooves or other injuries. Additionally, there was no evidence in the lubricant concentrate of any of the diluted lubricant dispersions of any dissociation of the components, even after extended standing.

EXAMPLE 2 1.98 kilograms of polyethylene, having a dropping point within the range of about 112 to 118 degrees centigrade, was heated in a heatable roll mill to about 130 degrees centigrade. 3.94 kilograms of montmorillonite were then rolled into the hot composition. The resulting mixture of the montmorillonite, impregnated with polyethylene, was allowed to cool and was then ground. The resulting finely ground material was then added to a mixture of 1.89 grams of olein, 0.16 kilogram of a nonionic emulsifier, 1.26 kilograms of water and 1.89 kilograms of the potas sium salt of fish oil fatty acid. The mixture was vigorously stirred and a white, paste-like lubricant concentrate was obtained. This concentrate was diluted with water as in Example 1, using ratios of concentrate to water within the range of 1:1 to 1:10, and the resulting lubricant dispersions were used in the deep drawing of steel sheet as in Example 1. In each instance, there was no evidence of injury to the formed parts and no settling or separation of the components of either the concentrate or the lubricant dispersions was found.

EXAMPLE 3 625 grams of polyethylene, having a dropping point within the range of 112 to 118 degrees centigrade, were heated to about degrees centigrade in a heatable kneader. 1,250 grams of finely divided aluminum hydroxide [Al(OH) were slowly introduced into the melt with intensive kneading.

Thereafter, a mixture of 600 grams of olein, 50 grams of nonionic emulsifier, and 500 grams of water were added to the still plastic composition. To this mixture was then added 69 grams of fatty acid dimer and 30 grams of triethanolamine. The resulting concentrate composition was then diluted with water, as in Example 1, and the water diluted lubricant compositions used int he cold forming of steel sheets, tubes and wires. In each instance, excellent results were obtained with no evidence of injury to the formed parts.

EXAMPLE 4 Conical steel articles, millimeters high with a lower diameter of '80 millimeters and an upper diameter of 35 millimeters were deep drawn from 1.2 millimeter thick cold strip steel, in eight steps, using a commercial aqueous soap-oil emulsion lubricant to which had been added 25 to 40 grams per liter of molybdenum disulfide (M05 It was found that after 500 strokes in the drawing, sufficiently severe seizing of the drawing tools occurred that the tools had to be repaired. Thereafter, the molybdenum disulfide in the lubricant composition was replaced with 12 grams per liter of the aluminum hydroxide impregnated with polyethylene, prepared in accordance with the procedure of Example 3. Using this lubricant, it was found that 30,000 sheet articles were drawn without damage to either the drawing tools or the pieces being worked.

When it was attempted to clean the drawn articles produced using the molybdenum disulfide containing lubricant, it was found that the lubricant could not be removed from the surface of the articles by any of the normal wetcleaning methods, including alkaline cleaning, acid pickling, or organic solvent degreasing. In contrast, the drawn articles formed using the lubricant of the present invention were completely cleaned, even after storage for one month, by dipping for 10 minutes, at 98 degrees centigrade, in an aqueous solution containing 40 grams per liter of an alkaline cleaner, which cleaner consisted of sodium hydroxide, sodium metasilicate and an emulsifier.

The procedure of the preceding example is repeated, using as the thermoplastic material polypropylene, polyisobutylene, a polyamide, a polyurethane, a polyacrylamide, and a polyurea, in place of the polyethylene. In each instance, impregnation of the pores of the inorganic plgment material with the thermoplastic is obtained and m each instance, the lubricant composition formed gives comparable results in cleanability and lubricating effectiveness.

While there have been described various embodiments of the invention, the compositions and methods described are not intended to be understood as limiting the scope of the invention as changes therein are possible and it s intended that each element recited in any of the followmg claims is not to be understood as limiting the scope of the invention as changes therein are possible and it is intended that each element recited in any of the followmg claims is to be understood as referring to all equivalent elements for accomplishing substantially the same results in substantially the same or equivalent manner, it being intended to cover the invention broadly in whatever form its principle may be utilized.

What is claimed is:

1. A lubricant composition for use in the cold forming of metals which comprises a liquid phase and a solid phase the solid phase being dispersed in the liquid phase, said liquid phase comprising at least one of a fatty lubricant material and Water and the solid phase comprising at least one porous, capillary-active inorganic pigment,

swellable in alkaline solution, the pores of which pigment are at least partially impregnated with a thermoplastic resin.

2. The lubricant composition as claimed in claim 1 wherein the inorganic pigment impregnated with the thermoplastic resin is present in an amount within the range of about 1 to 30% by weight of the lubricant composition.

3. The lubricant composition as claimed in claim 2 wherein the fatty lubricant material is selected from the group consisting of fats, oils, fatty acids and soaps of fatty acids, containing from 12 to 30 carbon atoms.

4. The lubricant composition as claimed in claim 3 wherein the inorganic pigment is aluminum hydroxide.

5. The lubricant composition as claimed in claim 4 wherein the thermoplastic resin with which the inorganic pigment is impregnated is polyethylene having a dropping point within the range of 95 to 120 degrees centigrade.

6. A method of deforming metal surfaces which comprises contacting the metal surface to be deformed with the liquid lubricant composition as claimed in claim 1, forming a lubricant coating on the metal surface and thereafter deforming the thus-lubricant coated metal surface.

7. The method as claimed in claim 6 wherein the inorganic pigment impregnated with the thermoplastic resin in the lubricant composition is present in an amount within the range of about 1 to percent by Weight of the lubricant composition.

8. The method as claimed in claim 7 wherein the fatty lubricant material in the lubricant composition is selected from the group consisting of fats, oils, fatty acids, and

References Cited UNITED STATES PATENTS 3,392,117 7/1968 Glasson 252-17 DANIEL E. WYMAN, Primary Examiner.

L. VAUGHN, Assistant Examiner.

U.S. C1. X.R. 

